Caption: Coloured scanning electron micrograph (SEM) of hooks from a hooks and loops fastener, a two-sheet material used to fasten clothes and other fabrics. Most commonly, one sheet consists of hooks (seen here), the other of loops. When the two materials are pushed together the hooks attach to the loops, forming a secure bond, but one that can easily be undone. Some fasteners are made of just hooks. The hook and loop fasteners have been used for many applications where a temporary bond is required. It is especially popular in clothing where it replaces buttons or zippers, and is used as a shoe fastener. A stronger version of the hook and loop material has even made it possible to create semi-permanent bonds where higher stress applications are needed. Hook and loop fasteners made from stainless steel are used in the automotive industry to attach parts such as bumpers. Magnification: x4.5 when shortest axis printed at 25 millimetres.